While various configurations of piping systems exist, one embodiment mates system components by use of a flange at each end of a pipe, valve, bulkhead, or the like. A gasket material is disposed therebetween, and a plurality of bores are disposed around the perimeter of the mating flanges. In one configuration, a first flange has threaded bores configured to receive bolts, machine screws, or the like, and a second flange is a through-bore configured with a clearance fit between the aforementioned threaded fastener. When the head of the fastener is tightened against the face of the through-bore flange, the second flange is pulled into contact with the first flange. In another configuration, bores on both flanges are through-holes, and a bolt and nut combination clamps the two flanges into contact with the gasket. The relation between the two flange planes is optimally parallel, and the thickness of the gasket material prevents the flange faces from touching. The resulting gap of the completed joint may approach 0.25 inches.
The flanged pipe, caps, valves, or other flanged accessory will be fabricated by selecting materials and dimensions that will support the pressure and structural considerations of the system. This will often result in heavy and unwieldy components that require (or at least benefit from), mechanical lifting aids. Slings, chains, and cables may be employed with overhead lifting aids and other rigging apparatus.
The state of the art requires that a lifting eye be welded to the face or edge of the flange. This eye results in a an undesirable protuberance, necessitates the use of a certified welder with accompanying weld quality testing, and significant time and money may be expended to prepare for the assembly of each flanged component.
Therefore there exists a need for attaching lifting apparatus to blind flanges, without welding and without interfering with the flange bolting process.